"I predict that the last mainframe will be unplugged on March 15, 1996." – Stewart Alsop, former InfoWorld editor-in-chief and stigmatism sufferer.

I can't help but tease Stewart a little over that prediction, made in 1991. It's not to rub his nose in it; he was always very friendly when I encountered him in the early days of my career, and it's a shame he's no longer in journalism. To his credit, he ate crow with a bit of self-deprecating humor a few years later:

"It's clear that corporate customers still like to have centrally controlled, very predictable, reliable computing systems – exactly the kind of systems that IBM specializes in," he said in February 2002.

And now we are celebrating 50 years of IBM making mainframes a viable technology for computing. They are still chugging along, with more than half of enterprise applications still using on them to complete transactions.

The mainframe, of course, is the pinnacle of reliability. A CA exec once joked with me that if a mainframe crashed more than three times in a year, it was considered an unreliable computer. If Windows crashed three times a day, it was a good day. The joke carried more weight in 1994 than it does now.

Let's be real. IBM dominates the mainframe world today. There are other players hanging in there but Big Blue has the market share and mindshare. And even though hardware isn't even 10% of IBM's business these days, good luck trying to out-innovate Big Blue. I don't think anyone else could have kept the mainframe going the way IBM has.

So what's kept the mainframe alive? Some of it was necessity and some of it was simply entrenchment. We may have Itanium and SPARC systems still in use 20 years from now. But mostly it was that the mainframe adapted with the times and adopted the newest trends for its own use. For example:

- Linux: As Linux took off, IBM embraced it and made a port to the mainframe. A lot of early Linux servers were recycled Windows NT and NetWare servers, but IBM made mainframes a consolidation platform, and that paid off well.

- New languages: The mainframe would be dead if it just stuck to COBOL. C++ has migrated to the mainframe, as has Java. Java apps run on mainframes have reduced latency to zero as the applications interacted in real-time with the data hosted on the mainframe.

- Virtualization & Partitioning: While you upstarts at VMware and Citrix try to get your arms around partition the umpteen x86 servers sprawled over a space many times the size of a mainframe, the mainframe was doing hardware partitioning and virtualization in firmware decades ago. CPU time, memory and storage were all defined with a few switches in firmware, something x86 won't do for a long time.

- Cloud computing: IBM has just announced new cloud initiative in conjunction with the mainframe's silver anniversary. The IBM Enterprise Cloud System is configured at the factory for rapid deployment, orchestration and monitoring of up to 6,000 virtual machines in one system. Last year, IBM released the zEnterprise BC12 (Business Class) entry-level mainframe for big data analytics and cloud computing while offering up to 55% savings over a comparable x86 system.

Fluidity and adaptation – and IBM's deep pockets – have kept the mainframe viable and will keep it viable for the foreseeable future. It's also something to note regarding the routine predictions of the demise of the PC. The PC does not have any one giant propelling innovation and it sure isn't adapting to the times very much. So there's a prediction that may prove more accurate.